Tubular pump



Nov, 10, 1970 A. L. RIDER ETAL TUBULAR PUMP Filed Sept. 23, 1968 UnitedStates Patent US. Cl. 418-48 7 Claims ABSTRACT OF THE DISCLOSURE Thedisclosure pertains to a tubular pump of the progressive cavity typeincluding a rotor, a drive shaft confined within a casing defining aninterior passage into which a fluid is delivered for movement out of thedischarge end of the pump, and a universal joint coupling between saiddrive shaft and said rotor consisting of a pair of universal jointsarranged back to back, a first drive pin connectingan outer end of oneof said joints to said drive shaft, a second drive pin connecting theouter end of the other of said pair of joints to said rotor, togetherwith a fluid filled boot secured in enveloping relation to said couplingfor preventing collapse of the boot and protecting said universal jointsfrom damage by the pumped fluid.

As is perhaps well known, a progressive cavity pump comprises a singlethread rotor inside a double thread unit or stator which carries thefluid to be pumped with positive pressure and continuous flow. In suchpumps, the axis of the rotor follows a circular path and in the oppositedirection from the movement of the rotor and, of course, the diameter ofsuch circular path will vary with the size of the rotor. Means fordriving the rotor can take the form of either a flexible cable, or adouble universal joint between a drive shaft and rotor, or a singleuniversal joint between a drive shaft and the rotor, and a flexiblestator, or a pin connected rod pinned at one end to the drive shaft andthe rotor at its other end. The present invention is directed to thelast mentioned type of drive means, of which the prior designs have beenunsatisfactory because of the frequent requirement of replacing thedrive pins, drive shaft, connecting rod and rotor, whereas a preferredembodiment of our invention is capable of operation for approximately800 days without replacement of pins or other parts.

A primary object of our present invention is to provide a tubular pumpof increased reliability and with a reduction in maintenance expensefrom a standpoint of time and money.

Another important object of the invention is to provide a tubular pumpof the indicated nature which is additionally characterized by theelimination of the necessity of having stainless to stainless movingparts and permitting the use of less expensive and better metals.

A still further object of our invention is to provide a tubular pump ofthe aforementioned character which includes a member permitting thepumping of food products or fluids of foods that would otherwise subjectthe pump parts to corrosion and abrasion.

Another object of the invention is to provide a tubular pump of theindicated nature which enables the replacement of the entire universaljoint coupling as a unit, or removal and replacement of but one or morecomponents thereof separately.

Other objects of the invention, together with some of the advantageousfeatures thereof, will appear from the following description of apreferred embodiment of the invention which is illustrated in theaccompanying drawings. It is to be understood, however, that I am not tobe limited to the precise embodiment shown, nor to the precisearrangement of the component parts thereof, as

my invention, as defined in the appended claims, can be embodied in aplurality and variety of forms.

Referring to the drawings:

FIG. 1 is a side elevational view, partly in section, and partly brokenaway, of a preferred embodiment of our invention.

FIG. 2 is a broken top plan view, partly in section of a preferredembodiment of the invention, partly broken away to illustrate theconstruction.

FIG. 3 is a perspective view, partly broken away to illustratecomponents of the universal joint coupling of a preferred embodiment ofthe invention.

In its preferred form, the tubular pump of our present invention, asadapted to be driven by a uni-directional motor or a reversing motorrotating a motor shaft, preferably comprises, in combination with asource of fluid, a casing defining an interior passage for said fluid, arotor, a stator encompassing said rotor and supported by said casing;said stator defining in association with said rotor a series ofprogressive cavities therebetween which are in communication with oneanother with said passage as well as with a discharge outlet of saidcasing, together with a universal joint coupling connecting said driveshaft and said rotor and consisting of a pair of universal joints,(preferably of the so-called Hookes type), an intermediate shaft betweensaid pair of universal joints; one of said pair of joints being mountedat its outer end on said drive shaft and pin-connected thereto, and theother of said pair of joints being pin-connected at its outer end tosaid stub shaft and said rotor, and an endless protector boot envelopingsaid coupling and containing a filler material.

As particularly illustrated in FIG. 3 of the annexed drawings, weprovide an elongated tubular casing 11 affording a pump body which canbe cast from iron but preferably is cast from stainless steel in orderthat the pump can elfectively handle fluids that might be damaging toiron such as corrode the metal or subject it to abrasion. The casing 11defines an interior passage 12 for the reception of material through aninlet 13 and for flow of such material to the discharge end 14 of thepump. As shown in FIG. 1, the pump is placed in driving connection withdriving means such as the shaft 15 of a motor, not shown, provided witha coupling 20, by means of a drive shaft 16 having a key-way 17 thereincooperating through a key 17' on shaft 15. The drive shaft 16 is mountedfor rotation on the longitudinal axis of the pump by conventional sealedfront and rear bearings 18 and 19, respectively, which are supported andheld against lateral displacement within the casing 11 by means ofinterior shoulders 21 and 22 respectively, formed on the inner wall ofthe casing. Preferably, the bearings 18 and 19 are tapered rollerbearings which are adjusted for end play by adjustment nuts 23 and 24.An oil seal 26 at the forward end of the pump body 11 is provided toprevent the escape of lubricant in the usual manner with a similar shaftseal 26 in a plate at the other end of the bearing housing 31, and astandard shaft seal 27 sealing against a plate 28 likewise is providedas customary. Of course, a stufling box type of packing can be usedinstead of shaft seal 27. Through-bolts 29 and 30 serves to hold thesevarious components together and to an outer flange 31 of the pump body.As illustrated, suitable pump supports 32 and 3-3 for carrying thecasing in an elevated position in relation to the ground or othersurface may be provided adjacent to opposite ends of the casing ill,such supports including uprights 34- and 3 5 bolted by means of boltsnot shown to flanges on the pump body.

In accordance with our present invention, we provide in combination witha standard assembly of rotor 38 and stator 39 supported in theconventional manner with the pump casing 11, a specially constructeduniversal joint coupling which is designed generally by the referencenumeral 41 in the accompanying drawings. As shown particularly in FIG.2, our improved universal joint coupling is wholly confined and housedwithin a protective envelope 42 which preferably is in the form of aboot or sleeve and preferably fabricated of Neoprene which is chemicallyinert to an appreciable number or extent to all fluids that might bepumped through the pump body. The interior of the Neoprene boot orsleeve 42 is filled with grease or with a tasteless, odorless,relatively non-toxic, noncompressible, non-corrosive, semi-fluid, suchas a silicone compound in order to keep the sleeve from collapsing underexternal pressure during operation or otherwise. The universal jointcoupling 41 is connected at one end to the drive shaft 16 by means of adrive pin 43 in order to transmit both axial load and torque, and issimilarly connected by means of a drive pin 44 to the rotor 38, seeespecially FIGS. 1 and 2 of the annexed drawings.

In order to reduce manufacturing costs to a minimum and yet afford auniversal joint and connections to the drive shaft and to the pump rotorwhich will be highly effective in that motion between the drive pins andconnecting stubshaft is eliminated thereby reducing wear on such pins toan absolute minimum, we provide in our improved universal joint coupling41 which comprises two so-called Hookes type universal joints consistingof a pair of needle bearings 46 and 47, a pair of yoke-carried crosses51 and 52, together with yokes 56 and 57 which support needle bearings46 and 47 and partially carry the crosses 51 and 52, respectively,additional yokes 58 and 59 for supporting the crosses 51 and 52; saidyokes extending laterally in opposite directions from yoke heads 60, seeFIG. 2, as well as additional yokes 61 and 61 for supporting needlebearings 63 and 63', respectively; the latter yokes extending laterallyin opposite directions from yoke heads 60 and 62. The coupling 41 alsoincludes an intermediate shaft or spacer 64 which can be a separate unitwelded to yoke heads 60 or can be formed integral with the coupling, asshown. Such intermediate shaft or spacer 64 can be lengthened as desiredto reduce the angular motion of the coupling 41 for larger sizes ofpumps. As shown in FIG. 2, drive shaft 16 extends into a flanged hub 66of coupling 41 and is pin-connected thereto by drive pin 43. At theopposite end of the coupling we provide a stub shaft 48 which istelescopically fitted within the inner end of rotor 38 and which ispreferably formed integral with the adjacent flanged end 67 of thecoupling 41; such stub shaft 48 being pin-connected to rotor 38 by drivepin 44.

As illustrated particularly in FIG. 2, the opposed end flanged hub 66and flanged end 67 which are pin-connected to drive shaft 16 and to stubshaft 48, respectively, and are so fabricated as to provide on each endthereof a flat periphery 68 and 69, respectively, which receive thedeformed extremities 71 and 72 of the Neoprene boot or sleeve 42. Wedetachably secure the boot in place by means of steel annular bands 73and 74 which are slipped over the deformed extremities of the bootfirmly to hold the boot upon such flanges 66 and 67.

The mountings of the rotor and stator 38 and 39 can be as desired. Asusual, a compression fit is provided between the metal rotor and therubber stator in order to reduce slippage, with through-bolts 78 and 79extending between end plates 81 and 82, and with the ends of stator 39bearings against said end plates which hold suitable O-rings to retainthe stator in operative position and sealed. The rotor 38 can befabricated of either tool steel or stainless steel and is covered with aheavy layer of chrome to resist abrasion. If the material to be pumpedis a food substance, such as citrus fruit juices or the like, stainlesssteel should be used for the rotor. The stator is conveniently formedfrom natural or a synthetic rubber, or other suitable material, and asshown in FIG. 1 forms with the rotor 38 a series of cavities which areprogressive from one end of the stator communicating with interiorpassage 12 to its opposite end at the discharge end 14 of the casing,and thus carry the fluid in the pumping action from the inlet to theoutlet as the rotor 38 turns within the stator 39. Since sealing-O-rings are provided and are located at the joints of the rubber statorand metal shell. carbon steel instead of stainless steel can be used,and threading of the stator shell also is thus eliminated. It is also tobe observed that the parts of our improved pump which are in contactwith the fluid being pumped are fabricated of Neoprene and stainlesssteel and, accordingly, food products can readily be pumped in ourimprovement which products would corrode pump bodies and parts made ofcarbon steel.

It is also to be noted that the complete flexible universal jointcoupling 41 can be replaced as a unit, or the coupling can bereconditioned by replacing the neoprene sleeve 42 separately as well asreplacing wearing parts as required.

We claim:

1. A tubular pump comprising, in combination with a motor shaft and asource of fluid to be pumped, a casing defining an interior passage intowhich said fluid is fed, a rotor in said casing, a stator surroundingsaid rotor and defining therewith progressive cavities communicatingwith said interior passage and with the discharge end of said casing, adrive shaft, a stub shaft, a universal joint coupling between said driveshaft and said rotor; said universal joint coupling comprising twoHookes type universal joints with the outer end of one of said twouniversal joints mounted on said drive shaft and pin-connected thereto,and with the outer stub shaft end of the other of said two universaljoints pin-connected to said rotor, and a fluid-filled protective bootenveloping said universal joint coupling.

2. A tubular pump as defined in claim 1 wherein said protective bootconsists of a Neoprene sleeve and the fluid filling the same isnon-compressible in order to maintain the size and shape of said bootand to prevent collapse thereof.

3. A tubular pump as defined in claim 1 wherein said two universaljoints are arranged to face in opposite directions, and a spacerinterposed between and two universal joints.

4. In a tubular pump of the progressive cavity type including a statorand a rotor, means for driving said rotor comprising, in combinationwith a motor shaft, a drive shaft connected to said motor shaft, astub-shaft, a universal joint coupling; said universal joint couplingcomprising a pair of Hookes type universal joints, a first drive pinconnecting the outer end of one of said pair of universal joints to saiddrive shaft, a second drive pin connecting the outer stub shaft end ofthe other of said pair of universal joints to said rotor, and a Neoprenefluid-filled sleeve enveloping said universal joint coupling.

5. In a tubular pump as defined in claim 4 wherein said universal jointcoupling comprises a hub at one extremity thereof, a flanged end at theother extremity thereof, a first pair of flange yokes welded to said huband to said flanged end and arranged in opposed longitudinalrelationship to one another, a second pair of flange yokes welded tosaid hub and said flanged end of said coupling arranged in opposedtransverse relationship to one another at approximately ninety degreesin respect to said first pair of flange yokes; each of said yokes havingan opening therein, bearings supported by the openings in said flangeyokes, cross-members oscillatably supported in said bearings and astub-shaft welded to said flanged end of said coupling.

6. In a tubular pump as defined in claim 5, and a protectivefluid-filled sleeve clamped to and enveloping said universal jointcoupling.

7. A tubular pump as defined in claim 6, and a chemically-inert,non-compressible, tasteless, odorless semi- 6 fluid in said sleeve formaintaining the shape and size 3,324,801 6/1967 Fernholtz. thereof andfor keeping said sleeve from collapsing. 3,340,814 9/ 1967 Streicher.

References Cited FOREIGN PATENTS UNITED STATES PATENTS 5 602,794 3/1960Italy. 2,695,694 11/1954 Seinfeld. 2,915,979 12/1959 Bourke et a1. MARKNEWMAN Pnmary Examme 2,924,180 2/1960 Bourke et a1. W. J. GOODLIN,Assistant Examiner 3,097,609 7/1963 Nechine.

